IR Sensor
Further Reading
8
®
Intensity vs. Emissivity
Using the TD-8580 Thermal Cavity, measure the radiation intensity
emitted by different surfaces at the same temperature. How do the color
and texture of surfaces affect the radiated intensity? Compare the
intensity from a surface to the intensity from a cavity of the same
temperature.
Radiated Power vs. Input Power of a Light Bulb
Measure the voltage and current applied to a small light bulb
*
, and the
radiation intensity emitted by it. Calculate the input electrical power,
and the total radiated power. How do they compare?
Second Law of Thermodynamics
The second law of thermodynamics states that heat tends to flow from a
hotter object to a cooler object. The objects do not have to be in contact
for this to occur because heat can be transferred through radiation.
Measure the net radiation intensity of an object that is cooler than the
sensor. In what direction is energy flowing? Allow the cool object and
the sensor to come to the same temperature. What happens to the
energy flow?
Further Reading
At www.dexterresearch.com follow the “Technical Briefs” link for
further information on thermopile detectors and radiometery.
KRS-5 Window Transmittance
TD-8580 Thermal Cavity
*PASCO part EM-8627 is
a pack of 25 light bulbs
that work well for this
experiment. They can be
used with Light Bulb
Sockets (EM-8630,
10-pack), and a power
supply capable of 300
mA at 2 V.
The PASPORT
Voltage/Current Sensor,
PS-2115 can be used to
measure the electrical
power supplied to the
bulb.
.1
.2
.3
.4
.5
.6
.7
.8
.9
1.0
2.0
3.0 4.0 5.0
10
20
30
40
50
100
0
10
20
30
40
50
60
70
80
90
100
Wavelength (
m
m)
Transmitt
ance (%)
Summary of Contents for PASPORT PS-2148
Page 10: ......
